From: Jérôme Hénin (
Date: Mon Apr 18 2016 - 04:17:27 CDT

If I understand correctly, you have predefined groups of atoms, then I
think you can't avoid a little bit of scripting, eg. calculating the center
of mass of every group and testing each one for your criterion.


On 17 April 2016 at 11:32, Khuong Truong Gia <> wrote:

> Dear all,
> I want to select a group of atoms that the z of center of mass of the
> group is below Zo value.
> Is it possible in VMD.
> Thank you very much,
> Khuong